1. Field of the Invention
The present invention relates to an image generation apparatus regarding copy machines, laser beam printers, facsimile terminals and plotter machines.
2. Description of the Related Art
Image generation apparatuses that make color images have been widely used for or applied to color copy machines, printers and facsimile terminals, plotter machines etc. and moreover applied to multi-function printers (MFP), such as those shown in references 1-3. Such image generation apparatus develops images by forming a latent image on the surface of an image carrier holder and transfer developing agent such as toner to the latent image. Next to such development process, the image generation is completed by transferring the developed images onto recording medium such as a piece of paper and fixing the images in a process such that the transferred images are fixed using a fixing member such as fixing belt etc.
In repeating such image fixing process, abrasion and/or scratch are often made on the surface of the fixing member. As a concrete example, carrying out to repeat the fixing process for the A4 size paper laid in the longitudinal direction (that is to pass the paper in the longitudinal direction along the machine) using an image generation apparatus that enables to use copy paper of both A4 and A3 sizes, longitudinal streak scratches are made at the positions, on the surface of the fixing belt, which are the longitudinal peripheries of A4 conventional paper. Such streak scratches are made due to paper debris (such as that of binder or additive) which is divorced from the paper by cutting machine process. The paper debris is attached to both longitudinal peripheries of the paper and abrades the surface of the fixing belt. When a fixing process is carried out using A4 and/or A3 size paper laid in transverse direction (that is to pass the paper in the transverse direction along the machine), a grazing streak comes out to the surface of the images. The appearance of this grazing streak looses the quality of the developed image.
The conventional technologies that may relate to the present invention are found in Japanese Publication of Patent Applications Nos. H5-113739, 2007-34068 and 2006-251165 (called reference 1, reference 2 and reference 3, respectively, hereinafter), all of which are incorporated by reference.
The inventions described in the references 1 to 3 disclose countermeasures that are to prevent such degradation of the image quality. For example, an optical sensor, that detects the reflected light on the surface of a fuser roller to which light is emitted from a light source, is attached to the image generation apparatus described in the reference 1. According to the intensity of the reflected light detected by the optical sensor, the reflectivity of the surface of the fuser roller is calculated. The image generation apparatus generates an alarm when the reflectivity is lower than a predetermined value since the lowering is caused by scratches on the surface of the fuser roller, offset or degradation of a surface condition thereof. People judge the time of exchanging of the fuser roller.